multi: enable optional route blinding feature

lnrpc/lightning.proto

@@ -4311,6 +4311,8 @@ enum FeatureBit {
     ANCHORS_OPT = 21;
     ANCHORS_ZERO_FEE_HTLC_REQ = 22;
     ANCHORS_ZERO_FEE_HTLC_OPT = 23;
+    ROUTE_BLINDING_REQUIRED = 24;
+    ROUTE_BLINDING_OPTIONAL = 25;
     AMP_REQ = 30;
     AMP_OPT = 31;
 }